Unbreakable and impervious ring of moulded synthetic material for package tins



Feb. 6, 1962 G. MAULAZ 3,019,936

UNBREAKABLE AND IMPERVIOUS RING OF MOULDED SYNTHETIC MATERIAL FORPACKAGE TINS Filed Nov. 28, 1960 /n /emor GEORGES MAULAZ United StatesPatent 3019 936 UNBREAKABLE ANli llVIPERVIOUS RING OF MOULDED SYNTHETICMATERIAL FOR PACK- AGE TINS Unbreakable and impervious rings of mouldedsynthetic material are already known, which are designed to be fixed,for example by setting, on the one hand on the body of a package tinand, on the other hand, on a lid'closing this tin, to unite this tin andits lid and ensure a vacuumtight closure. These rings are provided, onthe one hand, with two peripheral grooves defining between them a stripdesigned to be torn away when the tin is opened for the first time and,on the other hand, a tongue integral with the portion included betweenthe two grooves, this tongue serving to tear this strip.

The moulding of such a ring with its tongue presents the followingdifficulties:

The moulding must be effected by means of a slide mould and the problemis to give the tongue such a shape that once the ring and the tonguehave been moulded into a single element, the mould may be opened, thatis to say that the slides may be separated from the core of the mould.Up to the present, these difiiculties have not been solved.

The invention aims at providing a ring of such shape that thesedifliculties disappear. It has for object an unbreakable and imperviousring, of the type indicated, which is characterized in that the abovementioned strip is provided, in its part adjacent to the base of thetongue, over its whole width, with a thickness which diminishesprogressively up to this base, in order to facilitate the initial stageof the tearing, the outer surface of the strip in the part thus thinnedbeing tangential, at the point of minimum thickness of this strip, to acylinder coaxial to the ring.

The accompanying drawing shows, by way of example, one embodiment of thering according to the invention and of the mould serving for itsmanufacture.

FIG. 1 is a perspective view showing a part of a cylindrical metallictin provided with its lid and with this embodiment of the ring.

FIG. 2 is a partial longitudinal view in section, on a large scale, ofthe tin, its lid and the ring.

FIG. 3 is a partial cross sectional view of the slide mould employed inthe manufacture of the ring according to FIGS. 1 and 2 showing theclosed mould and the ring which has just been moulded therein.

FIG. 4 shows the same members as FIG. 3 but in the open position of themould, while the ring is still on the core of the mould.

FIG. 5 is a view along 5-5 of FIG. 4.

FIG. 6 is a partial cross sectional view of'the ring visible in FIGS. 3and 4 but after deformation of the tongue.

The ring 1 is of moulded synthetic material and it is designed to befixed, by a setting 2, on the body 3 of a cylindrical metallic tin. Itis designed to be fixed, on the other hand, by a setting 4, on a lid 5,also metallic and closing this tin. This ring has for function to joinas one the tin body 3 and the lid 5, to ensure a vacuumtight closure ofthe tin and moreover to guarantee the unbreakability of the tin. Byunbreakability is to be understood, according to custom, that the tincannot be opened without destruction of the entirety of the ring, thuspreventing any fraudulent opening and reclosing of the tin.

The ring 1 is provided, as is known, with two peripheral 3,619,936Patented Feb. 6, 1962 tearing grooves 6, 7, parallel, defining betweenthem a strip 8 designed to be torn when the tin is opened for the firsttime. It is obvious that, at the time of this tearing, the ring is tornalong the grooves 6 and 7. A tongue 9, of a piece with the ring 1 andintegral with the strip 8, serves to tear this strip.

The ring shown differs from known constructions by the followingcharacteristics:

The strip 8, which is seen in cross section in FIGS. 3 and 4, isprovided, in its part adjacent to the base 10 of the tongue 9, over itswhole width, with a thickness diminishing progressively up to this base,in order to facilitate the initial stage of the tearing. The outersurface 110i the strip 8, in the part thus thinned, is tangential, atthe point 12 of minimum thickness of the strip, to a geometricalcylinder coaxial to the ring.

The junction-line of the base 10 of the tongue 9 with I the strip 8, onthe side where the latter is thinned, has

the shape of a chevron 13 the point of which is in the middle of thestrip 8, where it is the thinnest. The ends 14 and 15 of the chevroneach coincide with the bottom of one of the tearing grooves 6, 7. Thethinning of the strip 8 at 12 and the obliqueness of the line 13facilitate the beginning of the tearing from 12, along 13. The fact thatthe ends 14, 15 of the line 13 coincide with the bottom of the grooves6, 7 facilitates the continuation of the tearing along these grooves. Inorder to manufacture the ring described, use is made of a slide-mould,of which one sees the core at 16, one of the slides at 17 and the otherslide at 18.

In order to form'the tongue 9 and the thinned part (19 in FIG. 3) of thering, during moulding, the slide 17 forming an outer element of themould, comprises a bladeshaped part 2% having two surfaces 21, 22 ofgeneral flat form and parallel. These surfaces are further parallel tothe direction of the reciprocating motion of this slide. When the slide17 is in the operative position (FIG. 3),

. these surfaces 21, 22 are tangential to geometrical cylinders coaxialto the core of the mould. The surface 21 is provided to form the surface11, that is to say the thinned part of the tearing strip 8, whereas thesurface 22 is provided to form the inner surface 23 of the tongue 9. Dueto this tangential arrangement of the surfaces 21 and 22, it isohviousthat the slide 17 may be separated from the core after moulding,without any difficulty. This arrangement givesa particularly simple andreliable solution of the moulding problem not solved up to the presentto which reference was made in the beginning.

The slide 18 comprises a part having a generally flatshaped surface 24,provided to form the outer surface 25 of the tongue 9. In this example,the surface 24 is parallel to the surfaces 21 and 22 and to thedirection of the reciprocating motion of the slide 18 which is the sameas for the slide 17.

In the example shown, the surfaces 23 and 25 of the tongue are providedwith slight roughnesses designed to facilitate the tearing operation ofthe strip. The presence of these roughnesses permits of holding thistongue more easily between the fingers during this operation.

In FIG. 6, there is shown the tongue 9 folded flat against the innersurface of the ring 1. This folding operation is effected aftermoulding, for example by heat softening the base 10 of the tongue andthen exerting a radial pressure on the latter. This deformation of thetongue aims simply at avoiding damage thereto during package ortransport of the tins.

According to modifications, the ring could be fixed to the tin and tothe lid not by settings, but by gluing or by soldering; the tin and thelid could not be of cylindrical shape; they could also be of anothermaterial than metal, for example of plastic material.

'3 What I claim is: 1. In an unbreakable and impervious ring of mouldedsynthetic material fixed at one edge on the body of a package tin and atthe other edge on a lid closing said tin for surface of said strip inthe portion of diminishing thickness being tangential to a cylindercoaxial to said ring.

2. vA strip as claimed in claim 1, further comprising a junction linebetween the base of the tongue and the portion of the strip having athickness diminishing progressively up to the .base of said tongue, saidjunction line being oblique relative to the parallel edges of said stripto facilitate the beginning of the tearing.

3. In an unbreakable and impervious ring of moulded synthetic materialfixed at one edge on the body of a package tin and at the other edge ona lid closing said tin and said lid and ensuring an airtightclosuretherebetween,

a strip, two peripheral and parallel tearing grooves defining the widthof said strip, a tongue integral with said strip and serving to tearsaid strip along said grooves, said strip having a thickness diminishingprogressively up to the base of said tongue to facilitate the initialstage of tearing, the outer surface of said strip in the portion ofdiminishing thickness being tangential to a cylinder coaxial to saidring, and a junction line between the base of the tongue and the portionof the strip having a thickness diminishing progressively up to the baseof said tongue, said junction line having the shape of a chevron, thecenter point of said chevron beingin the middle of said strip at the endof the portion of diminishing thickness of said strip.

4. A strip as claimed in claim 3, wherein the end points of said chevroncoincide with the bottoms of said tearing grooves.

References Cited in the tile of this patent UNITED STATES PATENTS424,982 Hidden Apr. 8, 1890 2,433,683 Coyle Dec. 30, '1947 2,747,345Plastino May 29, 1956

